Helen-

You aren't getting many responses here because your question is far too encompassing. For anyone to give you even a general run down on the differences between American Cha and International Cha would take a great deal of space. This in fact, and I mean no offense here, is certainly something that your instructor should have made extrememly clear to you as you learned each style. For you to be asking this question makes me really wonder if your instructor is doing what he's getting paid to do!

The best I can suggest in such a brief space is that you take a lesson specifically on the differences between Int. Cha and Am. Cha. Just mastering the differences in the basic pattern would take most beginners and some intermediates a whole hour or more!

Best of luck to you...KC